Conventionally, an electronic device such as a digital camera or a mobile terminal with camera includes a camera module having a solid state imaging device. The solid state imaging device has multiple photoelectric conversion elements arranged two-dimensionally corresponding to each pixel of a captured image.
Each of the photoelectric conversion elements is provided on a semiconductor layer. It photoelectrically converts light, which is incident through an insulating layer, a color filter, and a microlens stacked on the side of the semiconductor layer where light enters, into charges in an amount according to the amount of the received light, and stores the charges as signal charges indicating brightness of each pixel. A light shielding portion for shielding light incident from a specific direction on each photoelectric conversion element is provided in the insulating layer formed between the photoelectric conversion element and the color filter.
For example, the photoelectric conversion element for detecting a phase difference formed for detecting a focus of an imaging optical system has a light shielding portion provided on its light receiving surface for covering a part of the light receiving surface in order to pupil-divide the incident light. A light shielding portion that shields light incident from the color filter corresponding to the adjacent photoelectric conversion element is provided between the photoelectric conversion elements used for the image capture, viewed from the side where light enters.
In the solid state imaging device described above, the incident light might irregularly reflect on the side face of the light shielding portion to deteriorate light-receiving sensitivity. If the light shielding portion is made thin, the irregular reflection can be reduced. However, a part of a fine pattern on the light shielding portion might be lost due to electric or mechanical stress. On the other hand, when the light shielding portion is made thick, flatness is difficult to secure, so that an air bubble called a void is generated in the insulating layer during a step of burying the light shielding portion with the insulating layer. Such void causes deterioration in the light-receiving sensitivity.